The typical American diet can be classified as anything but healthy. According to the ARS Food Survey Group, 50% of Americans eat only one serving of whole grains per day, 59% do not eat enough vegetables and 76% do not meet daily fruit recommendations (Cleveland, L. E., et al., Pyramid Servings Data, ARS Food Survey Research Group.) Over 80% of American women do not consume enough dairy, while the intake of meats, fats and sweets greatly exceed recommendations. These eating habits result in a deficiency of nutrients and contribute to the rising incidence of health problems experienced by younger and younger members of the population (Kranz, S. et. al., Dietary fiber intake by American preschoolers is associated with more nutrient-dense foods; J. Amer. Diet. Assoc. 105:221, 2005; Lytle, L., Nutritional issues for adolescents, J. Amer. Diet. Assoc. 102:58, 2002). In addition, poor food choices have increased the incidence of obesity to 31%, and more than 64% of American adults are considered to be overweight. The problem doesn't stop there. The percentage of young children and adolescents who are overweight or obese has been steadily increasing since 1991 (Kopkin, J. P. et. al., Preventing childhood obesity: Health in the balance-Executive Summary, J. Amer. Diet. Assoc. 105:131, 2005).
Health problems related to weight are now second only to tobacco use as the leading of cause of preventable deaths (Mokdad, A. H., et. al., Actual causes of death in the Unites States, JAMA 291:1238, 2004). It is estimated that preventable weight-related illness costs the nation approximately $99.2 billion every year and that this cost is more than the cost estimated for tobacco and alcohol use combined. (National Institutes of Diabetes and Digestive and Kidney Diseases, Weight Control Information Network. Statistics Related to Overweight and Obesity). When unhealthy, highly processed foods are consumed regularly, nutrient deficiencies result, increasing the incidence of health problems such as heart disease, high blood pressure and type 2 diabetes (Cordain, L. et. al., Origins and evolution of the Western diet: health implications for the 21st century. Amer. J. Clin. Nutr. 81: 342, 2005).
While the obesity epidemic has risen rapidly in the last three decades, it cannot be accounted for by changes within the human gene pool. However, the trillions of prokaryotic bacteria that reside within the human gastrointestinal tract constitute a much larger genetic pool than that which can be found in the eukaryotic cells that constitute the human body (Bajzer, M. and R. J. Seeley, Obesity and gut flora. Nature. 444:1009, 2006). While the human genome takes generations to change, genetic contributions by changing populations of bacterial cells require mere days. It has been noted that the obesity epidemic has certain characteristics indicative of an infectious nature (Bray, G. A. et al., Beyond energy balance: There is more to obesity than kilocalories. J. Amer. Diet. Assoc. 105:S17, 2005). These bacterial populations, and subsequently their contribution to the physiological functioning of the eukaryotic cells, can change very quickly and could account for the infectious characteristic of the epidemic.
It has been recognized for some time that the human gut is the largest immune organ in the body, containing 65% of the immune tissue overall and contributing up to 80% of the immunoglobulin-producing tissue (Benmark, S., Gut microenvironment and immune function. Curr. Opin. Clin. Nutrit. Meta. Care. 2:1, 1999; Brandzaeg, P. et. al., Immunology and immunopathology of the human gut mucosa, humoral immunity and intraepithelial lymphocytes. Gastroenterology, 97:1562, 1989). In addition, several authors have noted that bacteria play a significant role in genetic expression within the eukaryotic cells of the human body (Muzmanian, S. K., et. al., An immunomodulatory molecule of symbiotic bacteria directs maturation of the host immune system. Cell 122:107, 2005; Rath, H. C. et. al., Normal luminal bacteria, especially Bacteriodes species, mediate chronic colitis, gastritis and arthritis in HLA-B27/Human beta-2 microglobin transgenic rats. J. Clin. Invest. 89:945, 1996; Lopez-Barado, Y. S. et. al., Bacterial exposure induces and activates matrilysin in mucosal epithelial cells. J. Cell. Biol. 148 (6):1305, 2000; Wang, Q. et. al., A bacterial carbohydrate links innate and adaptive responses through Toll-like receptor-2. J. Exp. Med. 203 (13):2853, 2006; Frick, J. S., et. al., Identification of commensal bacterial strains that modulate Yersinia enterocolitica and dextran sodium sulfate-induced inflammatory responses: Implications for the development of probiotics. Infect. Immun. 75 (7):3490, 2007; Kim, J. M., et. al., Nuclear factor-kappa B activation pathway in intestinal epithelial cells is a major gene expression and neutrophil migration induced by Bacteroides fragilis endotoxin. Clin. Exp. Immunol. 130:59, 2002). These data support the role that bacterial populations play in the physiological function of genetic expression within the eukaryotic cells of the human host, perhaps providing a key to stemming the obesity epidemic.
There have been many animal research studies that have utilized germ-free animals as well as animals that have established microbial populations. In 1993, results of a study were published on the effect of protozoa on metabolism and concentrations of bacteria and fungi in the hind gut of the Shetland pony (Moore and Dehority, J. Anim. Sci., 71:3350). These animals were fistulated in both the cecum and the colon to allow easy access to the contents of the gastrointestinal tract for research purposes. Defaunation (i.e., removing a segment of the established microbial populations of an animal) was also outlined in this publication. Defaunation followed by establishment of rumen protozoa from a fistulated sheep was then accomplished (Moore, unpublished data).
Procedures utilized in these trials to remove debris and much of the microbial populations from the equine hind gut are remarkably similar to the safe and effective procedures currently used by the medical community to prepare patients for a colonoscopy. It is therefore hypothesized that microbial populations in the human gastrointestinal tract could be changed by utilizing these procedures, followed by inoculation with a probiotic to establish friendly populations of bacteria more conducive to weight loss.
In 2006, researchers reported that microbiota containing higher concentrations of the Bacteroidetes bacteria obtained from the gut of a “lean” mouse were inoculated into germ-free mice, resulting in the subject mice having significantly less body fat than when “obese microbiota” containing differing microorganisms were used for inoculation (Tumbaugh et. al., An obesity-associated gut microbiome with increased capacity for energy harvest, Nature, 444:1027). These results indicate that the bacterial populations colonizing the human subject may play a role in the harvesting of energy from the host's diet.
Several scientists at the Stanford University School of Medicine reported similar findings in human subjects. Forty-two patients who had successfully undergone bariatric surgery were placed into one of two groups, a treatment group receiving 2.4 billion live colony forming units of Lactobacillus bacteria per day or a control group which received a placebo. After six months, the treatment group had lost 4% more weight than the control group and had higher Gastrointestinal Related Quality of Life Scores than the placebo group (Woodad, G. A., et. al., Probiotics improve weight loss, GI-related quality of life and H2 breath tests after gastric bypass surgery: A prospective, randomized trial. Digestive Disease Week Conference, Abstract #343, May 19, 2008, San Diego, Calif.). Lactobacillus cultures have seldom been indicated for weight loss.
Accordingly, it is hypothesized that successful gastrointestinal establishment of a probiotics culture specifically formulated and scientifically demonstrated to decrease weight gain, such as Bacteriodes cultures (as is discussed below), may significantly improve weight loss in persons identified as overweight or obese and may help prevent weight gain in those who are already lean.